Setting ACL Inheritance on ZFS Files in Verbose Format
You can determine how ACLs are inherited or not inherited on files and directories. By default, ACLs are not propagated. If you set a non-trivial ACL on a directory, the ACL is not inherited by any subsequent directory. You must specify the inheritance of an ACL on a file or directory.
In addition, two ACL properties are provided that can be set globally on file systems: aclinherit and aclmode. By default, aclinherit is set to restricted and aclmode is set to groupmask.
For more information, see ACL Inheritance.
Example 8–6 Granting Default ACL Inheritance
By default, ACLs are not propagated through a directory structure.
In the following example, a non-trivial ACE of read_data/write_data/execute is applied for user gozer on test.dir.
# chmod A+user:gozer:read_data/write_data/execute:allow test.dir
# ls -dv test.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:02 test.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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If a test.dir subdirectory is created, the ACE for user gozer is not propagated. User gozer would only have access to sub.dir if the permissions on sub.dir granted him access as the file owner, group member, or everyone@.
# mkdir test.dir/sub.dir
# ls -dv test.dir/sub.dir
drwxr-xr-x 2 root root 2 Aug 31 13:26 test.dir/sub.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data:deny
3:group@:list_directory/read_data/execute:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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Example 8–7 Granting ACL Inheritance on Files and Directories
This series of examples identify the file and directory ACEs that are applied when the file_inherit flag is set.
In the following example, read_data/write_data permissions are added for files in the test.dir directory for user gozer so that he has read access on any newly created files.
# chmod A+user:gozer:read_data/write_data:file_inherit:allow test2.dir
# ls -dv test2.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:26 test2.dir
0:user:gozer:read_data/write_data:file_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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In the following example, user gozer's permissions are applied on the newly created test2.dir/file.2 file. The ACL inheritance granted, read_data:file_inherit:allow, means user gozer can read the contents of any newly created file.
# touch test2.dir/file.2
# ls -v test2.dir/file.2
-rw-r--r--+ 1 root root 0 Aug 31 13:27 test2.dir/file.2
0:user:gozer:write_data:deny
1:user:gozer:read_data/write_data:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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Because the aclmode for this file is set to the default mode, groupmask, user gozer does not have write_data permission on file.2 because the group permission of the file does not allow it.
Note the inherit_only permission, which is applied when the file_inherit or dir_inherit flags are set, is used to propagate the ACL through the directory structure. As such, user gozer is only granted or denied permission from everyone@ permissions unless he is the owner of the file or a member of the owning group of the file. For example:
# mkdir test2.dir/subdir.2
# ls -dv test2.dir/subdir.2
drwxr-xr-x+ 2 root root 2 Aug 31 13:28 test2.dir/subdir.2
0:user:gozer:list_directory/read_data/add_file/write_data:file_inherit
/inherit_only:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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The following series of examples identify the file and directory ACLs that are applied when both the file_inherit and dir_inherit flags are set.
In the following example, user gozer is granted read, write, and execute permissions that are inherited for newly created files and directories.
# chmod A+user:gozer:read_data/write_data/execute:file_inherit/dir_inherit:allow
test3.dir
# ls -dv test3.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:29 test3.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/dir_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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The inherited text in the output below is an informational message that indicates that the ACE is inherited.
# touch test3.dir/file.3
# ls -v test3.dir/file.3
-rw-r--r--+ 1 root root 0 Jun 20 14:44 test3.dir/file.3
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:inherited:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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# mkdir test3.dir/subdir.1
# ls -dv test3.dir/subdir.1
drwxr-xr-x+ 2 root root 2 Jun 20 14:45 test3.dir/subdir.1
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/dir_inherit/inherit_only/inherited:allow
1:user:gozer:add_file/write_data:deny
2:user:gozer:list_directory/read_data/add_file/write_data/execute
:inherited:allow
3:owner@::deny
4:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
5:group@:add_file/write_data/add_subdirectory/append_data:deny
6:group@:list_directory/read_data/execute:allow
7:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
8:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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In these examples, because the permission bits of the parent directory for group@ and everyone@ deny write and execute permissions, user gozer is denied write and execute permissions. The default aclmode property is restricted, which means that write_data and execute permissions are not inherited.
In the following example, user gozer is granted read, write, and execute permissions that are inherited for newly created files, but are not propagated to subsequent contents of the directory.
# chmod A+user:gozer:read_data/write_data/execute:file_inherit/no_propagate:allow
test4.dir
# ls -dv test4.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:34 test4.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:file_inherit/no_propagate:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example illustrates, when a new subdirectory is created, user gozer's read_data/write_data/execute permission for files are not propagated to the new sub4.dir directory.
mkdir test4.dir/sub4.dir
# ls -dv test4.dir/sub4.dir
drwxr-xr-x 2 root root 2 Aug 31 13:35 test4.dir/sub4.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data:deny
3:group@:list_directory/read_data/execute:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example illustrates, gozer's read_data/write_data/execute permission for files is propagated to the newly created file.
# touch test4.dir/file.4
# ls -v test4.dir/file.4
-rw-r--r--+ 1 root root 0 Jun 20 15:15 test4.dir/file.4
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:inherited:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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Example 8–8 ACL Inheritance With ACL Mode Set to Pass Through
If the aclmode property on the tank/cindys file system is set to passthrough, then user gozer would inherit the ACL applied on test4.dir for the newly created file.4 as follows:
# zfs set aclmode=passthrough tank/cindys
# touch test4.dir/file.4
# ls -v test4.dir/file.4
-rw-r--r--+ 1 root root 0 Jun 20 15:19 test4.dir/file.4
0:user:gozer:write_data/execute:deny
1:user:gozer:read_data/write_data/execute:inherited:allow
2:owner@:execute:deny
3:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
4:group@:write_data/append_data/execute:deny
5:group@:read_data:allow
6:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
7:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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This output illustrates that the read_data/write_data/execute:allow:file_inherit/dir_inherit ACL that was set on the parent directory, test4.dir, is passed through to user gozer.
Example 8–9 ACL Inheritance With ACL Mode Set to Discard
If the aclmode property on a file system is set to discard, then ACLs can potentially be discarded when the permission bits on a directory change. For example:
# zfs set aclmode=discard tank/cindys
# chmod A+user:gozer:read_data/write_data/execute:dir_inherit:allow test5.dir
# ls -dv test5.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:40 test5.dir
0:user:gozer:list_directory/read_data/add_file/write_data/execute
:dir_inherit:allow
1:owner@::deny
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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If, at a later time, you decide to tighten the permission bits on a directory, the non-trivial ACL is discarded. For example:
# chmod 744 test5.dir
# ls -dv test5.dir
drwxr--r-- 2 root root 2 Aug 31 13:40 test5.dir
0:owner@::deny
1:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
2:group@:add_file/write_data/add_subdirectory/append_data/execute:deny
3:group@:list_directory/read_data:allow
4:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/execute/write_attributes/write_acl/write_owner:deny
5:everyone@:list_directory/read_data/read_xattr/read_attributes/read_acl
/synchronize:allow
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Example 8–10 ACL Inheritance With ACL Inherit Mode Set to Noallow
In the following example, two non-trivial ACLs with file inheritance are set. One ACL allows read_data permission, and one ACL denies read_data permission. This example also illustrates how you can specify two ACEs in the same chmod command.
# zfs set aclinherit=noallow tank/cindys
# chmod A+user:gozer:read_data:file_inherit:deny,user:lp:read_data:file_inherit:allow
test6.dir
# ls -dv test6.dir
drwxr-xr-x+ 2 root root 2 Aug 31 13:43 test6.dir
0:user:gozer:read_data:file_inherit:deny
1:user:lp:read_data:file_inherit:allow
2:owner@::deny
3:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/write_xattr/execute/write_attributes/write_acl
/write_owner:allow
4:group@:add_file/write_data/add_subdirectory/append_data:deny
5:group@:list_directory/read_data/execute:allow
6:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
/write_attributes/write_acl/write_owner:deny
7:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
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As the following example shows, when a new file is created, the ACL that allows read_data permission is discarded.
# touch test6.dir/file.6
# ls -v test6.dir/file.6
-rw-r--r-- 1 root root 0 Aug 31 13:44 test6.dir/file.6
0:owner@:execute:deny
1:owner@:read_data/write_data/append_data/write_xattr/write_attributes
/write_acl/write_owner:allow
2:group@:write_data/append_data/execute:deny
3:group@:read_data:allow
4:everyone@:write_data/append_data/write_xattr/execute/write_attributes
/write_acl/write_owner:deny
5:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow
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